Prime Minister Jacinda Ardern was among other leaders to react. "Watching the removal of a woman's fundamental right to make decisions over their own body is incredibly upsetting."
The two Americas of blue and red will become clearly defined by states that allow abortion services and those that don't. It's expected there will be bans in at least 20 states.
The court ruling, which polls show is not what the majority of Americans wanted to happen, sparked large protests at the weekend. But will it result in a high Democratic turnout at Midterm voting stations in November? The Democrats need gains in states, particularly at governor level, to stop bans. In Congress they would need 60 Senate votes to enshrine reproductive rights in law.
Legal experts say the ruling shows there will likely be other targets for the court such as abortion drugs, contraception, and same-sex marriage.
There could be a lot of interference in people's lives.
Over the past seven years people have got used to being surprised by - but then absorbing and mentally normalising - very dramatic events, from the Trump presidency, to Brexit, race-linked killings, gun rampages, environmental disasters, the pandemic and war in Europe.
Warnings that more calamity is probably coming tend to be ineffective. Natural scepticism, the difficulty of being sure, and awareness that fear of what could happen is sometimes overblown, probably play a part in that.
Most people are also busy with their lives and have low expectations of politics helping them. It's people heavily invested in a course of action who do the pushing while those on the sidelines think of reasons why a divisive move with big consequences hopefully won't occur.
President Vladimir Putin surprised many international political experts by going beyond sabre-rattling to invade Ukraine, despite the huge costs to people and economies that would bring.
Brexit never made much economic or political sense for the UK's future before the 2016 referendum, but enough voters were swayed into narrowly backing leaving the EU in a late swing. That situation has evolved: Two byelections on Friday featuring tactical opposition voting overturned gains the Conservatives made in Brexit's aftermath - increasing pressure on Prime Minister Boris Johnson.
The US House of Representative hearings have revealed the extent of Trump's brazen efforts to overturn the 2020 election result. Aside from the issue of prosecution, they have added to concerns over the 2024 presidential race. If Trump contests the next Republican primary and loses would he accept the result? If he becomes the party's nominee and then loses again could another attempt to overturn an election succeed?
There's potentially a lot of 'unthinkable' change ahead for people to think about.